Existing exports of data: object cannot be re-sized

[TechnoX]

I have got this error message a few times now, but I don't see a clear pattern on when it happens. Will update with more information when I found out!

[ERROR] [1529186693.127298]: bad callback: <function callback at 0x7f465b56aa28>
Traceback (most recent call last):
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/home/fredrik/home_ws/src/vizbox/backendbase.py", line 5, in callback
    cb(converted)
  File "/home/fredrik/home_ws/src/vizbox/server.py", line 91, in handle_challenge_step
    self.write_message(data)
  File "/usr/local/lib/python2.7/dist-packages/tornado/websocket.py", line 256, in write_message
    return self.ws_connection.write_message(message, binary=binary)
  File "/usr/local/lib/python2.7/dist-packages/tornado/websocket.py", line 801, in write_message
    fut = self._write_frame(True, opcode, message, flags=flags)
  File "/usr/local/lib/python2.7/dist-packages/tornado/websocket.py", line 780, in _write_frame
    return self.stream.write(frame)
  File "/usr/local/lib/python2.7/dist-packages/tornado/iostream.py", line 530, in write
    self._write_buffer.append(data)
  File "/usr/local/lib/python2.7/dist-packages/tornado/iostream.py", line 158, in append
    b += data
BufferError: Existing exports of data: object cannot be re-sized